Download Cell transformation

CELL TRANSFORMATION
RNDr. Jan Šrámek
[email protected]
2013
Seminar lesson of cell and molecular biologie
What is it today about
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Cell transformation
Characteristics of tranformed cells
Mechanisms of transformation
Carcinogenes
Tumors and their classification
Cancer therapy
Cell transformation
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What is cell transformation?
Cell transformation
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What is cell transformation?
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Process of transformation of normal cell that react to feedback
homeostatic mechanisms to cell with autonomous growth and
ability of invasion.
All cancer cell are transformed cell
But! Not all transformed cells are cancer cells (e.g. cells of cell
cultures)
Characteristics of tranformed cells
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What are typical transformed cells characteristics?
Characteristics of tranformed cells
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What are typical transformed cells characteristics?
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Independence on stimulatory cytokines
Loss of ‘anchorage dependence’
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Characteristics of tranformed cells
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What are typical transformed cells characteristics?
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Independence on stimulatory cytokines
Loss of ‘anchorage dependence’
Capability of non-regulated clonal growth and loss of contact inhibition
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Characteristics of tranformed cells
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What are typical transformed cells characteristics?
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Independence on stimulatory cytokines
Loss of ‘anchorage dependence’
Capability of non-regulated clonal growth and loss of contact inhibition
Immortality (no dependence on ‘lifespan limit’) and resistance to apoptosis
Inability to differentiate
Ability of induction of angiogenesis
Different cell surface molecules and chromosomal reconstruction (CD44, annexiny,
etc.)
Genetic instability
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Characteristics of tranformed cells
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What are typical transformed cells characteristics?
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Independence on stimulatory cytokines
Loss of ‘anchorage dependence’
Capability of non-regulated clonal growth and loss of contact inhibition
Immortality (no dependence on ‘lifespan limit’) and resistance to apoptosis
Inability to differentiate
Ability of induction of angiogenesis
Different cell surface molecules and chromosomal reconstruction (CD44, annexiny,
etc.)
Genetic instability
Abnormal proliferation in space and time represents basic characteristic of
transformed (tumor) cells.
Mechanisms of cell transformation
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1)
2)
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4)
5)
6)
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What is the nature of cell transformation mechanisms?
What are oncogenes and anti-oncogenes, name some.
How many mutations are approximately needed to cause cell
tranformation?
What are the most common genetic changes (types) during the cell
transformation process?
What is hypothetical probability of cancer development in human?
What can positively affect cancer incidence?
What can negatively affect cancer incidence?
Mechanisms of cell transformation
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What are typical transformed cells characteristics?
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Multistage process (cancer incidence correlates with age)
Multistage process
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Sequential acumulation of genetic changes (4–7 mutations), according to dozens of different genes.
Cancer cell
1. mutation
2. mutation
3. mutation
4. mutation
Mechanisms of cell transformation
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What are typical transformed cells characteristics?
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Multistage process (cancer incidence correlates with age)
Non-returnable process
Mechanisms of cell transformation
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What are typical transformed cells characteristics?
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Multistage process (cancer incidence correlates with age)
Non-returnable process
Under selection stress
Process under the selection stress
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Mechanisms of cell transformation
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Multistage process (cancer incidence correlates with age)
Non-returnable process
Under selection stress
Spontaneous x induced
Mechanisms of cell transformation
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Multistage process (cancer incidence correlates with age)
Non-returnable process
Under selection stress
Spontaneous x induced
Genetic changes (mutations)
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Cancer incidence is 10-8 (includes 4 mutations, spontaneous mutation incidence is 10-6 per one cell
division, number of cell divisions in human life is 1016; 10-6x4/1016 = 10-8)  1 human per 100 milion x
reality
Influence of other factor: carcinogens, immune system
Mechanisms of cell transformation
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Multistage process (cancer incidence correlates with age)
Non-returnable process
Under selection stress
Spontaneous x induced
Genetic changes (mutations)
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Cancer incidence is 10-8 (includes 4 mutations, spontaneous mutation incidence is 10-6 per one cell
division, number of cell divisions in human life is 1016; 10-6x4/1016 = 10-8)  1 human per 100 milion x
reality
Influence of other factor: carcinogens, immune system
Immune system
Cancer incidence
Cancer incidence
10-8
10-8
Carcinogens
Theory of immune survailence
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What is the nature of theory of immune survailence?
Theory of immune survailence
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What is the nature of theory of immune
survailence?
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Majority of cancer cells is eliminated by immune system
in organism (Tc-lymphocytes).
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Sooner, mean lifespan was about 35–40 years.
Nowadays, mean lifespan increased markedly in
western countries.
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Maximum efficiency of immune system is between 30–
40 years of life.
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Cancer incidance markedly higher after passing 40
years.
Cancer is a consequance of immune system
failure in cancer cells elimination.
The main role of genetic changes
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Accumulation of genetic changes (mutations)
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Primary role of oncogenes and antioncogenes (tumor-supressor genes)
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Change of function (quality) and/or level of expression (quantity) of onco/antioncogenes via:
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Point mutations
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Deletions
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Chromosomal translocations
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Gene amplifications
Change of quality × change of quantity
(c-abl)
(c-ras)
(c-myc, c-myb, N-ras))
Philadelphia chromosome
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Regulation domain
Tyrosin-kinase domain
Fusion of Bcr (22nd Chromosome) and of Abl genes (proto-oncogene [tyrosin kinase] of 9th
chromosome).
Bcr protein is extensively produced in lymphocytes and has unclear function and strong promotor.
Responsible for many types of leukemia.
Bcr/Abl fusion protein p210 has encrease tyrozin-kinase activity (no regulation domain)  no
regulation of signaling  marked change of quality.
Simultaneously, it has markedly higher expression rate (according to Bcr promotor)  marked
change of quantity.
Point mutation of c-ras gene
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Ras
Ras protein has GTP function
Signaling molecule
Mutation of c-ras gene leads to continuous activation of Ras protein  increase expression of proteins
stimulating cell division  tumor development
Carcinogens
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1.
What are carcinogens and how do they affect?
2.
Which tree main classes of carcinogens do we know?
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Name some of each basic type of carcinogen.
4.
By which mechanism chemical carcinogens cause cell transformation?
5.
What cause ion radiation?
6.
What cause UV radiation?
Carcinogens
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Cause genetic changes via interactions with DNA leading to cell
transformation.
Factors causing cell transformation:
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Chemical
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Physical
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Biological
Chemical carcinogens
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Cause transitions, transversions, bases modifications or covalentely bind to DNA
Bases analogs: 5-bromuracil (BU) – supersede T  base transition
Agens modifying bases:
HNO2: deamination of C on U, A on hX, G on X  transition
HSO-3: deamination of C on U  transition
NH2OH
H2N-O-CH3
Alkyl agent: alkylsulfates, N-alkyl-N-nitrosamines (nitrates). Alkyl C, T and G  block or
change base pairing, cause between- and interchain crossbonds  block of replication
and transcription
Psoralenes: intercalar agens, furocumarin, 8-metoxypsoralene
Pre-carcinogens: metabolic activation via specific enzymes (cyt. P450) is necessary
N-acetyl-2-aminofluoren (AAF), Benzo(a)pyren, Aflatoxins, Nitrates and others
Physical carcinogens
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Ionize radiation:
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dsDNA breaks → chromosomal translocations.
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generate crossbonds (covalent bond between antiparalel nucleotids)
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base modifications (8-hydroxyguanin, 5-hydroxymetyluracil…).
UV radiation: atom excitation  generate thymin dimers  block
of replication and transcription processes.
crossbonds
Breaks
crossbond
strand
strand
Biological carcinogens
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1.
Describe the mechanism of cancer cell development in a consequance of
the effect of oncogene virus?
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Biological carcinogens
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1.
2.
Describe the mechanism of cancer cell development in a consequance of
the effect of oncogene virus?
Which viruses (name examples) can affect as carcinogens?
Biological carcinogens
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Viruses:
 Oncogene RNA viruses: retroviruses (classical oncogenes):
 HIV – probably supporting function only, Kaposi sarcoma…
 Human lymphotropic virus type I and II (HLTV-1, HLTV-2) – T-leukemia,
lymphomas
 HCV – hepatocarcinomas
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Oncogene DNA viruses:
 Papovaviruses (HPV) – anogenital tumors
 Herpesviruses - Epstein-Barr virus (EBV) – lymphomas (BL, HD),
nasopharingeal carcinomas (NPC); and others (HCMV; HSV-2; KSHV)
 Hepadnaviruses - hepatitis B virus (HBV) - hepatocarcinomas
 Adenoviruses (animals)
HPV
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Virus genome is circular dsDNA (8 kb)
Protein E7
 Inhibition of Rb-proteinu
 Inactivation of p21Cip and p27Kip
 Abolishes inhibition effect of TGF- on growth of cells
 Causes development of multiple centrosomes
Protein E6
 p53 degradation (using of ubiquitin ligase E6AP)
 interact with Bak (inhibition of apoptosis)
 activate hTERT expression (activation of telomerase)
Genome is integrated in several places of host genome
Integration is specific according to genome of the virus – leads to
disorder of protein E2 expression (regulate E6 and E7 expression)
Effect of Papillomaviruses (Papovaviruses)
proteins E6 and E7 on cell transformation
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Effect of Papillomaviruses (Papovaviruses)
proteins E6 and E7 on cell transformation
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Biological carcinogens
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„
 Infectionous cancer“:
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Histiocytes
Dogs CTVT (Stickers sarcoma)
Non-viral parasitic cancer of Swan cells (DFTD) of Tasmanian devil (Sarcophilus
harrisii)
Tumor
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What is a tumor and what is its function in an organism?
How many transformed cells is sufficient for tumor development?
Where are tumors in an organism mostly developed?
What is the diference between benign and malign tumor?
How do we classify tumors?
What is metastasis and how is developed?
Tumor
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Structure consists of cancer and connective cells that are under the controle
of cancer cells (stroma and blood cells).
No physiological function in an organism.
Its growth is not in conformity with surrounding tissue and organism
homeostasis
Developed in places with high proliferating activity that are simultaneously
the most displayed to carcinogenes, i.e. mainly epithels (skin, lung, digestive
tract, but breast gland)
The only one transformed cell is sufficient to develope tumor! (clonal
character)
Tumors classification I
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According to its infiltration ability:
 Benign: solid bordered structure, located in one place, slow proliferation,
symtoms of local character.
 Malign: infiltrate surrounding tissues and using blood and lymphatic system the
whole body, in „infected“ tissues produce secondary tumors (metastases)
 primary x secondary secondary tumors.
Tumors classification II
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According to type of source cells:
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Carcinomas – tumors of epithelial cells (ca 89 % of human tumors)
Sarcomas – solid tumors developed from supporting or connective cells
(tissue) – muscle, bone, cartilage (ca 2 % of human tumors)
Leukemias and lymphomas – developed from hematopoietic cells and
immune cells (ca 8 % of human tumors)
Gliomas – developed from nerve tissue (ca 1 % of human tumors)
Tumors classification III
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According to affected organ (tissue):
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Breast carcinoma
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Colorectal carcinoma
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Cervical carcinoma
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Gland carcinoma
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Stomach cancer
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Ovarian carcinoma
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Leukemia
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And many others
Process of metastasis development
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Primary tumor
Secondary tumor - metastasis
Cancer therapy
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1.
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What are basic approaches in cancer therapy?
Which chemoterapeutics do we know and what is common mechanism of their effect?
What other preparates can be used?
What is gene therapy?
Cancer therapy
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Classical approach:
Local therapy – surgical strike, local radiation ( radiation)
Systematical approach (combinated with surgical strike and radiation) –
Chemotherapy
Chemotherapy:
Cytotoxic agents: cyclophosphamide, cisplatinum, methotrexate, doxorubicin
(interaction with DNA)
Cytostatics: Vinca alcaloides (vinblastine, vincristine)
Application of cytokines:
Inhibitors of cell proliferation and inductors of apoptosis: Interferones, TNF
Support influence of cytokines: IL-2, GM-CSF
Biological therapy (targeted therapy, [Gene therapy])
‘Antisense’ oligonucleotides: target to specific oncogenes
Transfection: functional anti-oncogenes
….
Biologicac therapy (targeted therapy)
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Use defensive capacity of immune system and/or targeted drugs
(modificators of immune response) – cause specificaly only (or mainly)
on specific type of cells (e.g. cancer cells or immune cells):
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Blocks, restore or reduce precesses that are responsible for tumor progression
Marks cancer cells to be well recognizable by immune system
Improve ability of some immune cells (T-lymphocytes, macrophags) to destroy cancer
cells
Changes growing ability of cancer cells
Blocks or restore processes responsible for cell tranformation
Improves ability of organism to repair or replace damaged cells injured by other
types of cancer therapy
Blocks cancer cells spreading
Biologicac therapy
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Preparation:
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Monoclonal antibodies
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Differenciacal therapy
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Inhibitors of proteasom, tyrosinkinases
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Anti-angiogene therapy
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Antisense oligonucleotides
High prices
Limited usage depending on these criterias:
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Tumor subtype
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Other types of cancer therapies are non-effective
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Undesirable effect of other types of cancer therapies
Monoclonal antibodies
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Biologicac therapy
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Preparation:
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Monoclonal antibodies
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Differenciacal therapy
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Inhibitors of proteasom, tyrosinkinases
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Anti-angiogene therapy
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Antisense oligonucleotides
High prices
Limited usage depending on these criterias:
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Tumor subtype
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Other types of cancer therapies are non-effective
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Undesirable effect of other types of cancer therapies
Differential therapy
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Developmental line
Differentiated cell
Progenitor cell
Mutations
Differentiated cell
Cancer cell
Specific drug
Biologicac therapy
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Preparation:
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Monoclonal antibodies
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Differenciacal therapy
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Inhibitors of proteasom, tyrosinkinases
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Anti-angiogene therapy
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Antisense oligonucleotides
High prices
Limited usage depending on these criterias:
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Tumor subtype
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Other types of cancer therapies are non-effective
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Undesirable effect of other types of cancer therapies
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Biologicac therapy
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Preparation:
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Monoclonal antibodies
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Differenciacal therapy
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Inhibitors of proteasom, tyrosinkinases
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Anti-angiogene therapy
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Antisense oligonucleotides
High prices
Limited usage depending on these criterias:
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Tumor subtype
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Other types of cancer therapies are non-effective
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Undesirable effect of other types of cancer therapies
Anti-angiogenesis therapy
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a) Cancer cells induce angiogenesis
c) Tumor have nutrition and growth
and release cells into the circulation
b) Vessel reacts by protrusion
d) anti-angiogene agens (white circles)
block angiogenesis
Biologicac therapy
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Preparation:
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Monoclonal antibodies
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Differenciacal therapy
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Inhibitors of proteasom, tyrosinkinases
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Anti-angiogene therapy
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Antisense oligonucleotides
High prices
Limited usage depending on these criterias:
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Tumor subtype
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Other types of cancer therapies are non-effective
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Undesirable effect of other types of cancer therapies
Antisense oligonucleotides
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Biologicac therapy
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Preparation:
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Monoclonal antibodies
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Differenciacal therapy
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Inhibitors of proteasom, tyrosinkinases
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Anti-angiogene therapy
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Antisense oligonucleotides
High prices
Limited usage depending on these criterias:
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Tumor subtype
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Other types of cancer therapies are non-effective
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Undesirable effect of other types of cancer therapies
Biological therapy (targeted therapy)
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Suitable types of tumors for biological therapy:
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Kidney tumors
Prostate tumors
Intestine tumors
Lung tumors
Breast gland tumors
Female genital tumors
Melanoma
Kaposi’s sarkoma
Thank you for your attention
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Next seminar lesson: Mechanisms of effect of oncogenes and tumor-supresor-genes
(no. 130)